Storm and Sanitary SSA Junction modeling

[Anonymous]

Has SSA been updated to model junction losses per HEC-22, 3rd edition?  Does it model losses per HEC-22, 2nd edition?

[Matt.Anderson]

No.   Based on the calculations it performs today, unlikely.   

[Anonymous]

Matt,

How does SSA calculate junction losses (what equation)?

[Anonymous]

Matt,

I found the equation the SSA uses to estimate junction losses.  How are the entrance and exist loss coefficients affected by benched inverts at a junction?  This scenario seems to be missing from the structure type and entrance design table.

Thanks,

Joseph

[Matt.Anderson · Accepted solution]

Joseph -

SSA uses a dated SWMM engine.  The last time SSA's engine was updated EPASWMM was 5.0.22, or at least 13 releases ago or more.

SWMM does not estimate losses at Junctions as it's not calculating an EGL.   It's up to the user to apply loss values.

[robert.dickinsonVR2DF]

As Matt says there are no losses at a junction (which is in InfoWorks ICM. BTW) but losses happen in the links. You can use Fixed or K*V^2/2g losses to at least have an additional head loss due to benching or bends etc.